The Internet Protocol (IP) Multimedia Subsystem (IMS) is an architectural framework for delivering IP-based multimedia services. A wireless transmit/receive unit (WTRU) may connect to an IMS through various access networks, including but not limited to networks based on technology such as UMTS Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE), Worldwide Interoperability for Microwave Access (WiMax), or Wireless Local Area Network (WLAN) technology. A WTRU may access the IMS through a packet-switched (PS) domain. Through the use of IMS Centralized Services (ICS), a WTRU may additionally access IMS services via a circuit-switched (CS) domain.
Inter-UE transfer (IUT) allows a communication session transfer from one WTRU to another. A transfer may occur when a user shares media with another user, when a user takes a session or session component and moves away from the device that is currently involved in the session, when a user wants to transfer media to devices more capable of handling media (i.e. a larger screen, clearer audio, etc.), when the device currently involved in the session has low battery or poor radio coverage, or when the remote end changes media characteristics or adds further media and the operation may not be performed well by a current source WTRU.
An inter-operator transfer may include a collaborative session between WRTUs. Usually at least one controller WTRU is involved in a collaborative session. Session invitations may be routed to a controller WTRU and a communication session may be directed to a device with controller capabilities. Devices may register their capabilities and may be prioritized over other devices for the purpose of receiving a communication session.
Instead of transferring a session, replicating some or all media components in a session may be desirable. For example, if a user wants to share an ongoing session with another user. However, it is difficult to distinguish between a request for the transfer of media components and a request for replication of media components. Also, it is difficult to determine if a device is able to perform replication and how often replication of a session may occur.